The present invention comprises a new and distinct cultivar of calla lily, botanically known as Zantedeschia sprengeri and hereinafter referred to by the cultivar name ‘Gran Paradiso’.
‘Gran Paradiso’ is a product of a planned breeding program which had the objective of creating Zantedeschia hybrids for cut flower production in a wide range of colors with a large, classic flower shape. The breeding program began in 1989 and the new cultivar is a seedling selected from the crossing of Zantedeschia sprengeri seedling Z030624 (female parent, unpatented) with Zantedeschia sprengeri variety ‘Treasure’ (male parent, unpatented). ‘Gran Paradiso’ was selected in 2008 by the inventor C. J. J. Randag in 't Zand, The Netherlands as one flowering plant within the progeny of the stated cross.
The first act of asexual reproduction of ‘Gran Paradiso’ by tissue culture was performed by the inventor in August of 2008 in 't Zand, The Netherlands. Further asexual reproductions by tissue culture at the same location has demonstrated that the combination of characteristics as herein disclosed for the new cultivar are retained and reproduced true to type through successive generations of asexual reproduction.
The following observations, measurements and comparisons describe plants at 12-14 weeks after planting grown in 't Zand, The Netherlands under greenhouse conditions which approximate those generally used in horticultural practice. Color references are made to The 2001 R.H.S. Colour Chart of The Royal Horticultural Society of London, except where general color terms of ordinary significance are used.
The present invention has not been evaluated under all possible environmental conditions. The phenotype may vary with variation in environment without a change in the genotype of the plant.
The following traits have been repeatedly observed and determined to basic characteristics of ‘Gran Paradiso’ which, in combination, distinguish this calla lily as a new and distinct cultivar:                1. Orange red-colored spathe;        2. Big spathe size        3. Tall flower stems and        4. High flower production.        
Further, when compared to calla lily plant named ‘Tresor’ (unpatented), the upper surface spathe color of ‘Tresor’ is Red Group RHS 46A and the lower surface spathe color of ‘Tresor’ varies between Yellow Group RHS 13B to 14A, while the upper surface spathe color of ‘Gran Paradiso’ varies between Orange Group RHS 25A to 25D and the lower surface spathe color varies between Yellow-Green Group RHS 144A and 144B. Further, ‘Gran Paradiso’ exhibits larger and more numerous leaf maculation spots than ‘Tresor’.
Table 1 provides similarities and differences of ‘Gran Paradiso’ to its parents Z030624 and Treasure
TABLE 1‘Gran Paradiso’SimilaritiesDifferencesZ030624Leaf shapeNumber of inflorescences (3-7)Spathe colorNo spots on leaves‘Treasure’Leaf shapeNumber of inflorescences (1-5)Spathe shape (Funnel)